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steer_offset_estimator#

Purpose#

The role of this node is to automatically calibrate steer_offset used in the vehicle_interface node.

The base steer offset value is 0 by default, which is standard, is updated iteratively with the loaded driving data. This module is supposed to be used in below straight driving situation. image

Inner-workings / Algorithms#

Estimates sequential steering offsets from kinematic model and state observations. image2 Calculate yaw rate error and then calculate steering error recursively by least squared method, for more details see updateSteeringOffset() function.

Inputs / Outputs#

Input#

Name Type Description
~/input/twist geometry_msgs::msg::TwistStamped vehicle twist
~/input/steer autoware_auto_vehicle_msgs::msg::SteeringReport steering

Output#

Name Type Description
~/output/steering_offset tier4_debug_msgs::msg::Float32Stamped steering offset
~/output/steering_offset_covariance tier4_debug_msgs::msg::Float32Stamped covariance of steering offset

Launch Calibrator#

After launching Autoware, run the steer_offset_estimator by the following command and then perform autonomous driving. Note: You can collect data with manual driving if it is possible to use the same vehicle interface as during autonomous driving (e.g. using a joystick).

ros2 launch steer_offset_estimator steer_offset_estimator.launch.xml

Or if you want to use rosbag files, run the following commands.

ros2 param set /use_sim_time true
ros2 bag play <rosbag_file> --clock

Parameters#

Params Description
steer_update_hz update hz
initial_covariance steer offset is larger than tolerance
forgetting_factor weight of using previous value
valid_min_velocity velocity below this value is not used
valid_max_steer steer above this value is not used
warn_steer_offset_deg warn if offset is above this value

Diagnostics#

The steer_offset_estimator publishes diagnostics message depending on the calibration status. Diagnostic type WARN indicates that the current steer_offset is estimated to be inaccurate. In this situation, it is strongly recommended to perform a re-calibration of the steer_offset.

Status Diagnostics Type Diagnostics message
No calibration required OK "Preparation"
Calibration Required WARN "Steer offset is larger than tolerance"

This diagnostics status can be also checked on the following ROS topic.

ros2 topic echo /vehicle/status/steering_offset